WASHINGTON — After a summer of setbacks, President Barack Obama summoned Congress to enact sweeping health care legislation Wednesday night, declaring the "time for bickering is over" and the moment has arrived to help millions who have insurance and many more without it.

Obama said the changes he has in mind would cost about $900 billion over decade, "less than we have spent on the Iraq and Afghanistan wars, and less than the tax cuts for the wealthiest few Americans" passed during the Bush administration.

In a televised speech to a joint session of Congress, Obama spoke in favor of an option for the federal government to sell insurance in competition with private industry. But he said he was open to alternatives that create choices for consumers.

Obama's speech came as the president and his allies in Congress readied an autumn campaign to enact his top domestic priority. While Democrats command strong majorities in both the House and Senate, neither chamber has acted on Obama's top domestic priority, missing numerous deadlines leaders had set for themselves.

In a fresh sign of urgency, Sen. Max Baucus, D-Mont., announced that his Senate Finance Committee would meet in two weeks to begin drafting legislation, whether or not a handful of Democrats and Republicans have come to an agreement. The panel is the last of five to act in Congress, and while the outcome is uncertain, it is the only one where bipartisanship has been given a chance to flourish.

Obama said there is widespread agreement on about 80 percent of what must be included in legislation. Any yet, criticizing Republicans without saying so, he added: "Instead of honest debate, we have seen scare tactics" and ideological warfare that offers no hope for compromise.

"Well, the time for bickering is over," he said. "The time for games has passed. Now is the season for action."

"I am not the first president to take up this cause, but I am determined to be the last," he added.

In a reflection of the stakes, White House aides mustered all the traditional pomp they could for a president who took office vowing to change Washington. The setting was a State of the Union-like joint session of Congress, attended by lawmakers, members of the Cabinet and diplomats.

The House was packed, and loud applause greeted the president when he walked down the center aisle of the House chamber.

Additionally, the White House invited as guests men and women who have suffered from high costs and insurance practices, seating them near first lady Michelle Obama. Vicki Kennedy, the widow of Sen. Edward M. Kennedy, D-Mass., was also on the guest list. Kennedy, who died last month, had made health care a career-long cause.

Obama intends to follow up the speech with an appearance Saturday in Minneapolis, the White House announced.

Despite deep-seated differences among lawmakers, Obama drew a standing ovation when he recounted stories of Americans whose coverage was denied or delayed by their insurers with catastrophic results.

"That is heartbreaking, it is wrong, and no one should me treated that way in the United States of America."

The president sought to cast his own plan as being in the comfortable political middle, rejecting both the government-run system that some liberals favor and the Republican-backed approach under which all consumers buy health insurance on their own.

Obama said the legislation he seeks would guarantee insurance to consumers, regardless of pre-existing medical conditions, as well as other protections. "As soon as I sign this bill, it will be against the law for insurance companies to drop your coverage when you get sick or water it down when you need it most," he added.